I have two more to add:
body LOCAL_OBFU_VIAGRA /(?:\b[vu]|\B(?:\\\/|\xCE\xBD))[\W_]{0,3}(?:[il1:\|\*\xCC-\xCF\xEC-\xEF\xA6]|\xC4[\xA8-\xB0]|\xC4\xBA|\xC4\xBC|\xC4\xBE|\xC5\x80|\xC5\x82|\xC7[\x8F-\x90]|\xD0[\x86-\x87]|\xD1[\x96-\x97]|\xCE\x8A|\xCE\x90|\xCE\x99|\xCE\xAA|\xCE\xAF|\xCE\xB9|\xCF\x8A)[\W_]{0,3}(?:[a4\*\@\xC0-\xC5\xAA\xE0-\xE5]|\/\\|\xC4[\x80-\x85]|\xC7[\x8D-\x8E]|\xC7[\xBA-\xBB]|\xCE\x86|\xCE\x91|\xCE\x94|\xCE\x9B|\xCE\xAC|\xCE\xB1|\xD0\x90|\xD0\xB0)[\W_]{0,3}(?:[g6]|\xC4[\x9C-\xA3]])[\W_]{0,3}(?:[r\xAE]|\xC5[\x94-\x99]|\xD1\x93)[\W_]{0,3}(?:[a4]\b|(?:[\*\@\xC0-\xC5\xAA\xE0-\xE5]|\/\\|\xC4[\x80-\x85]|\xC7[\x8D-\x8E]|\xC7[\xBA-\xBB]|\xCE\x86|\xCE\x91|\xCE\x94|\xCE\x9B|\xCE\xAC|\xCE\xB1|\xD0\x90|\xD0\xB0)\B)/i
score LOCAL_OBFU_VIAGRA 1.8
describe LOCAL_OBFU_VIAGRA Obfuscated 'VIAGRA' in body
The rule above will block obfuscated "Viagra" in the body of the message. The following rule does the same sort of thing but with special characters spelled out:
describe MANGLED_VIAGRA mangled viagra
body MANGLED_VIAGRA /(?!viagra)v{1,3}(?:[_\W]{0,5}|[viagra])[iÌÍÎÏìíîï\|1l\!](?:[_\W]{0,5}|[viagra])[aÀÁÂÃÄÅàáâãäå4\@](?:[_\W]{0,5}|[viagra])g(?:[_\W]{0,5}|[viagra])r(?:[_\W]{0,5}|[viagra])[aÀÁÂÃÄÅàáâãäå4\@]/i
score MANGLED_VIAGRA 2.5